You can add sprites. You just need to define them as mounts for a race.
Like for example humans, you'll probably want to go to /races/human/human_mounted/humanmounts_low.txt (humanmounts.txt is horses, the difference is the positioning of the leg: it's "shorter" in the non-horse poses)
There you'll just add like
Code:
#newitem
--- Pretty much any name an another mount doesn't already have
#name "tiger"
--- Only matters for for items that the game considers items, ie armor, shields and weapons.
#gameid -1
--- Replace with your tiger sprite:
#sprite /graphics/mounts/standard/serpent1.png
--- Doesn't matter if this really exists or not since it's just for indicating some #gameid is armor instead of weapon
#armor
--- Since it's a mount these mean the actual rider will be 7 pixels left from the normal position and 14 pixels below the normal position. You'll probably want to ignore these at first and then adjust them once you see your sprite in SpriteGen.
#offsetx -7
#offsety 14
--- mountedoverlay.txt in the same folder defines an overlay named "6" (yes, terrible name) which is pasted on top of everything after everything else is drawn. This is basically the mount's head and most visible on spider where it makes the leg look decent.
#needs overlay 6
--- #define commands define what stats the item should affect
#define "#size 3"
#define "#mapmove 2"
#define "#ap 18"
#define "#mounted"
#define "#weapon 19 --- Bite"
--- This is a bit different. You can just give it a number, but if you want the mount to be sacred/not sacred depending on the rider you'll need to go play with /nations/secondshapes.
#define "#secondtmpshape serpent1"
--- The +35 is there to indicate it increases gold cost, the other stuff don't have + or - so they just set the value to that.
#define "#gcost +35"
#define "#ressize 2"
#define "#enc 3"
--- The "animal serpent" #theme line is pretty important for summaries and generating somewhat coherent lineups
#theme "animal serpent"
#theme "light"
--- Guaranteed (it's a bit bugged so it isn't) prefix for units, ie most cavalry with this mount are "Serpent Cavalry"
#tag "guaranteedprefix serpent"
--- Maximum chest armor prot this mount can carry, minprot is the opposite. If you plan to make a mount with 0 to 100 armor, you probably want to split it to 0 to 12 and 13 to 100 versions with different gold cost increases.
#tag "maxprot 13"
#enditem
The reason I'm not very happy with just graphics is that writing those things to right places is actually usually more work than some weapon or mount or similiar.